Scale



July 1o, 192s. 1,676,295

-w. ls. SMITH SCALE y Filed May l2, 1926k 2 Sheet,s-Shee I 1 'HIM July 1o, 192s. 1,676,295

W. S. SMlTH SCALE Filed may 12, 192e l sheets-sheet 2 fill Patented July 10, 1928.

` UNITED STATES PATENT OFFICE. f

WALTER s. SMITH, or coLui/fiscus,joHI'o.f

SCALE.

Application filed nay 12 This invention relates to improvementsin` scales and is particularly directed to scales of the so called even balance type wherein aA centrally pivoted beam is provided with weight receivers mounted on its outer ends andA wherein a torsion element is provided for resisting deflection of the beam from other than a balanced or neutral position. As an example of a scale of this type reference is made to my prior patent issued Feb-- ruary 7, 1922, Number 1,405,634, wherein the torsion element referred to is disclosed as being associated with the indicator structure for denoting by multiplied movement the weighing positions of the beam. The

present invention has for an object the pro-V mounted in connection with the brace orr check rod structure, instead ofthe indicator mechanism, 'as `in my aforesaid patent,4

whereby several outstanding advantages are obtained, to-wit: more stable operation of the beam, the use of larger and more substantially constructed torsion elements and particularly ineconomy and facility in manufacture. 1

Another outstanding object of the present invention resides in the construction `of the knife edge'fulcrum supports for the bea-m and weight recessie-s, wherein said supports are each formed to include compound pivoted axes arranged in substantially perpendicular relative order 4so that thesupports will auton'iatically `adapt and align themselves with the position kof the cooperative l-:uife edge studs or trunnions, whereby through theen'uiloyment of the supports the friction due to the improper Vseating of the t-runnions in the supports is eliminated and' tolerances 1n manufacture provided which contributes materially toward economy `in the commercial production ofthe scale.A

lWiththese and other objects in view, as will appear as the description proceeds', the invention consists in the novelvfeatures of 1926. Serial No. 108,671.

construction, combinations of element-sand arrangements of parts hereinafter to be fully described and ed claims. Y

In -the accompanying drawings: Figure `l is a side elevation of the improved scale comprising the present invenpointed out in the append-` tlon, f

Figure 2 is a vertical sectional-view taken therethrough, f

Figure 3 is a detail perspective view showing the compound fulcrum support for the beam bearings,

Figure 4 is a detail vertical cross-sectional view on the line 4-4 of Figure l,

Figure 5 is a vertical sectional view takenthrough one of the fulcrum supports, Y

AFigure 6 is a similar view on the line 6-6 of Figure',

Figure 7 isa detail vertical sectional viewon the line 7-7 of Figure l,

Figure 8 is a plan view of the Vweighing beam or lever.

Referring more particularly to the struc-v tural details of the scale, as such details are organized inthe specific form of the invention herein'nselected for purposes of the pres-l eol entfdisclosure, the numeral l designates the metallic-base ofthe scale. This base may be in the form of a casting or stamping, as desired, and includes a substantially horizontal top wall 2, together with outwardly sloping side wiallsB. Thebottom of the housing is preferably open and the walls 2 and 3 serve to define an internal chamber 4, in which certain ofthe operating parts of the scale, to

be hereinafter described, `are situated.

Arranged upon the top wall 2, adjacent to the Vcenter ofthe base l, is a transversely disposed fulcrum'support which isdesignated in itsl entirety by the letter B which, in'this instance, partalres'of the form of a Ushaped yoke, comprising a horizontally extending portion 5 which is `screwed or otherwise secured tio the base l asfat 6 for convenience in asseniblyand manufacture. The upwardly directed 1egs 7 of the, support Bare provided with`verticallydisposed sockets 8, in whichY are received vertical pivots or studs 9 depending 'from blockv holders 10 which areV of metallic construction andare adaptable for rotation about the vertical axes provided by the studs 9. As shown in Figures 5 and 6, the lower surfaces of the holders 10 are smoothly finished to rest upon the correspondingly finished surfaces provided upon the extreme upper end of the legs 7, whereby a proper fitting and operating relationship is maintained between the legs 7 and the holders 10 to allow the latter to turn freely upon the upper ends of said legs. The holders 10, are, in turn, provided with recesses 11 in the upperport-ions thereof for the reception of seal fulcrum blocks 12 and the blocks 12 are provided with horizontally disposed openings arranged to register with vsimilar openings providedk in the holders 10 for the reception of a transversely extending pin 13 for each support, which pin extends perpendicularly to the corresponding stud 9, whereby each ofthe fulcrum blocks include a compound pivotal mounting permitting each block to yturn about both vertical and horizontal pivots. Each block 12 has its upper face provided with a V shaped notch 14 for the reception of the transversely extending knife edge trunnion 15 provided in connection with the medial portions of a weighing beam or lever 16. vThe trunnions 15 are rigidly positioned within slots 17 formed in the beam 16. It frequently hap-` pens in'y scale manufacture that the trunnion, which projects rigidly and in a horizontal and lateral direction from each side of the beam, are not in true alignment, or if in such alignment the receiving blocks therefor may be slightly offset from desired positions,'and for this reason the vertical pivots 9 are provided in cach of the fulcrum supports soas to adapt the latter automatically to these irregularities which inevitably appear in scale manufacture. On the other hand if the trunnions have the knife edges thereof disposed in other than -a true horizontal plane, the pins 13 are provided to allow the blocks 12 to swing in a vertical plane and to thereby properly and automatically seat the knife edges on their supporting bearings. By this construction scales may be produced in quantity production and yet high accuracy standards maintained, and, furthermore, the construction assures afleXible mounting, as it were, for the beam which prevents binding thereof inany of its weighing positions. If desired, the outer walls of the legs 7 may have fastened thereto plates 18 which extend Vupwardly and are provided with enlarged openings 19, adjacent to their upper ends, for the reception of pins 21 protruding laterally from the side of the beam 16. The plates 18 serve to confine the trunnions 15 upon the blocks 12 so as to overcome lateral shifting movement thereof beyond predetermined limits and, also, the plates serve to prevent undue vertical 'movement on the part of the trunnions 15 and the beam 16 with regard to the bearing ylongitudinally extending parallel bars blocks. A limited vertical movement is permitted so as to provide for the necessary flexibility in operation and the swinging movement within normal limits of the beam,

but the connection serves to overcome excess or abnormal movement.

, The beam is ofthe substantially rectangular form, disclosed Vin Figure 3 and includes 22 united by the end bars 23 on the transversely extending webs 2K1. The webs 24: are also joined with a longitudinally extending bar 25 lying between the bars 22.

Adjacent to the outer end of the beam the bars 22 are provided in the upper' surfaces thereof with slots for the reception of upstanding rigidly positioned knife edges 26, whichv are. adapted to engage with fulcrum blocks 27, shown particularly in Figure 7 and which corresponds in construction and operation to the adjustable fulcrum B heretofore described. rllhe blocks 27 are carried in connection with fulcrums C carried or pivotally connecting the weight receiver D with the end of the beam. As shown, however, the blocks 27 are pivotally united by means of horizontally extending pins 28 with block holders 29, which are positioned between the blocks 27 and offset projections 30 formed on the body portions 31 ofthe weight receivers D. The holders 29 are provided with. upwardly projecting vertically arranged pins 32, which are received within sockets provided in the projections 30, the pins 32 allowing the holders 29 to turn about vertical axes so that the' compound pivotal construction is provided by which the knife edges 26 and the fulcrums therefor are self adaptable to irregularities in alignment and other manufacturing era. The projections 30 may be provided with the tie plates 33, which correspond to the plates 18 in function and purpose. The lower ends of the plates 33 are provided with enlarged openings 34 for the reception of pins 35 projecting from the beam. The plates 33 serve to prevent complete separation between the knife edges 26 and the fulcrum blocks 27 but allow for ordinary, normal operating movement.

The weight receivers may be of any desired configuration depending upon the` purpose-and the nature of the body to be placed thereon. In this instance the weight receivers have been shown as provided with enlarged weight receiving pans 36, arranged above the body portions 31, and depending from said body portions are rigidly connected stems 37, which pass through openings 38formedin the top wall 2 ofthe base 1. The stems 37 are normally positioned in the chamber 11 of the base 1 and have their lower ends pivotally connected as at 39 with a longitudinally extending check rod 40, which extends parallel to the beam 16V and lun position midway `of the length of said chamber is a fixed stirriip 41 which, has its lower end `formed to include spaced depending legs 42 which terminate in smooth horizontal `walls for the reception of the ends of a transversely extending torsion strip 43'.

The ends of the strip are clamped to the legs 42 by means of clamping plates 44 which are screwed or otherwise secured to the legs 42 by the use of fastening elements 45, the arrangement. being such as to hold rigidly and firmly the ends of the strip 43 so as to restrain the latter in a positive manner against movement.` Between the legs 42 the central portion ofthe check rod 40 is situated and, in the present instance, the check rod is recessed as at. 46 for the reception of the transversely extending torsion strip and is rigidly clamped to said strip by means of clamping plates 47, held in the recesses 46 by screws or the like 48. Thus it will be apparent. that, should the scale elements be moved outof their normal or neutral position, the torsion strip 43 will be distorted and placed under stress because ofthe oscillatory movement of the check rod -structure with whichit is clamped adjacent to its central portion. l l Y Arising 'from the central portion of the base is a two part indicator housing 49, commonly termed the indicator tower. The central longitudinally extending bar portion 25 of the beam is inovably positioned within this tower by extending throught elongated openings() provided in the sides thereof, as shown in Figure 4. Upon the central portion of the bar 25 there is fixed an upwardly extending stirrup 5l provided with an upper yoke shaped extremity 52. Connected with the end of this extremity is a `band 53 which is arranged to pass over and is secured to, as at 54, a d-riiin 55, car-V ried in connection with a transversely extending shaft 56. `Connected with the drum is an upwardly directed indicator hand 57,v 'which 1s' arranged for movement upon' the` graduated surface 58 provided in the upper part of the tower 49. This surface and the top of the indicator hand is viewable from either side of the scale by means of transparent panels 159 arranged in openings 6 0 formedl in the side walls of the towel'. Normally, the torsion element 43 serves to maintain the beam and its associated indicator hand 57 in a normal `or neutral position wherein said'hand `occupies a central position with respect to the graduated surface 58, so that the defiectionbf the beam from its normal position may be observed to indicate both under and over weights. ABy spacing the drumshaft 56 from the fulcriim support B of the beam the movement of the hand V57 may be'multiplied as regards the increments of travel of said beam to any suitable extent in order to provide for con veniency and accuracy in the reading of the scale.

A dash pot 6l is connected, as usual, with the beam to stabilize its oscillation following the removal or application of weights to the beam, and if desired an adjustable poise may be utilized, of conventional design, to further control the beam balance. Inthe process of manufacturing the beam, I preferably mill or Vcut the central rece ses or slot-s 17 for the reception of the triinnions l5, both slots being produced by the single transverse cut, and, while the beam is supported on a permanent base, the. slots in one end of the beam for the knife edges 26 are produced, and then by turning the beam through 180 degrees the opposite ends thereof can be presentedto the cutter to produce theother set of slots in the opposite end of the beam for the reception of the knife edges; This method assures, without laying out distances, an exact spacing of the outer slots at positions located equidistantly from the central slot and overcomes a source of in-.v

accuracy and error heretofore present in the manufacture of scales of this kind. larly, in forming the knife edges on the trunnions, the plate coinprisingsaid trun-f nions are arranged in compact groups .in a

` holder and presented to `a grinding tool to bevel one side thereof. Then, by turning the holder, the opposite edges of the plate are similarly presented to the grinder so that when the latter finishes its operation, each plate will be perfectly beveled onopposi'te sides so that its edge will occupy the exact center of the thickness of each plate,

instead of being located to one side or the other of such center.

It will be seen that the present invention provides a scale of theeven balanced type which, as previously stated, lends itself readily to economial yet accurate.andV durable manufacture; `This is obtained by the features' of construction and ii'ianufacture above "set forth, including especially the compound pivotal bearings. for Vthe beam knife ledge trunnions by which the almost imperceptible errors in alignment and arrangement are compensated for `and over-v come without involving friction or binding of movable parts. I `consider this pivotal bearing construction to be of very considerable importan'ce in not only scale; of `the type herein disclosed but in vscales of any.-V

kind employing pivot .or knife edge fiilcrums arranged in aligning order; Again, the diirabilityiand ruggedness of the scale Ais considerably benetted by arranging the torsion strip vin connection' with the check structure of the scale, in that a large strip Simimay peated operations without fatiguing on the part of the metal comprising the strip or loss of its original form. Moreover, the position of the stripremovesit from the normal shock and jar of the scale and contributes materially to its accuracy and longevity. It will be observed that the torsion strip functions in the manner ot a pendulum in returning the beam to a neutral position, but it is an improvement on the pendulum principle in that the scale is not responsive to variation in level and may be placed on any supporting base, and will function normally irrespective ot the relation of the supporting surface of the base with respect to the horizontal,

What is claimed is:

LA scale comprising a pivoted beam, a

ycheck rod movablein pai-al elism with said.

beam, a torsion strip cooperative withv said check rod to maintain said beam normally in neutral position, an indicator tower arranged above said beam, a rotatable member mounted in said tower, a yoke rigidly carried by the central portion of said beam and including spaced arms arranged on opposite sides of said member, a flexible member having its ends connected with said arm and its central portionoperatively engaging said rotatable member, and. au indicator hand movable with said member and having its outer end arranged to travel adjacent to a graduated surface.

2. A scale comprising a pivoted beam, a tower arising from said beam, a stirrup fixed to the central portion of said beam and arrangedto oscillate with the latter within said tower, a rotatable member mounted within said tower and disposed between the diverging portions of said stirrup, a flexible band having the ends thereofconnected with the diverging portions of said. stirrup and the central portion thereof connected with said rotatable member, and an indicator. hand connected with said member and arranged for oscillation within said tower.

3. In ascale, a torsion strip, a pivoted beam normally maintained in a neutral position by said strip, a stirrup fixed to said beam to oscillate therewith and including upwardlydiverging arms, an independently mounted rotatable member arranged above said beam and situated between the diverging arms of said stirrup, a band connection between the diverging arms of said stirrup and said rotatable member, and an indieator hand movable with said rotatable member.

4. In a scale, a base, a beam, a pivotal con-l be used -fully capable of standing` reers and said supports permitting the holders to turn in a horizontal plane, said holders having the upper portions thereof provided with recesses, fulcrum blocks arranged to occupy said recesses, horizontally disposed pivotal connections mounting said blocks within said recesses to permit of vertical oscillation of said blocks, and a pair of fixed knife edge trunnions projecting laterally from said beam and engaging in V shaped notches provided in the upper surfaces of said. blocks.

.5. In a scale, afulcrum support comprising a base, aA holder, a vertical pivotal connection between said holder and base permitting the holder to turn in a horizontal plane, said holder having a recess provided therein, a block positioned within the recess of said holder, a horizontal pivotal connection between said holder and said `block permitting the latter/to swing in a vertical plane, and a movable member provided with a fixed laterally extending knife edge trunnion engaged with a V shaped notch provided in said block. f

6. In a scale, a base, a fulcrum support associated with said base comprising a holder. a vertical pivotal connection between said holder and said base permitting the holder to turn in a horizontal plane, saidholder being provided with a recess, a block positioned within said recess, a horizontally arranged pivotal connection uniting said block with said holder and permitting the block to turn in a substantially vertical plane, a movable.

member provided with a fixed laterally projecting trunnion having seated engagement with a V shaped notch provided in said.

block, and a tie plate connected with said base and having a loose connection with said movable member, said tie plate serving to confine the trunnion within the notch of said block.

7. In a scale. a base, a beam pivotally mounted on said base, said beam being formed Ato comprise longitudinally extending side bars, transversely extending Lconnecting webs, and a centrally located longitudinallyextending web connected with said transverse webs, a stirrup arising from said central web, and an indicating mechanism actuated by said stirrup.

8, In a scale, a base, a beam, a pivotal connection between the beam and the base comprising a U shaped support formed with bearings inthe upper ends thereof for the reception et vertically disposed pins, U shaped holders mounted on said pins permitting .said holders to turn in a horizontal plane, fulcrum blocks arranged within said holders, horizontally disposed pivotal connections uniting said blocks with said holdedge trunnions fixed to said beam and engaging with V shaped notches provided in l0. In a scale, a base, a beam, a pair of said blocks. transversely arranged trunnions projecting 9. In a scale7 a hase, a beam7 a pair of laterally from said beam, seats for the recep-` transversely arranged trunnions projecting tion of said trunnions mounted for ver- 5 laterally from said beam7 a pair of fulcrum tical oscillation upon horizontally turning 15 blocks for the reception of said trunnions, mcuntings having vertically disposed pivotal said blocks being positioned for vertical connections with said base. oscillation upon horizontally turning mount- In testimony whereof I airix my signature. ings having vertically disposed pivotal con- 10 nection With said base. y i Y VALTER S. SMITH. 

